Transferrin regulates mRNA levels of a gene involved in iron utilization in Entamoeba histolytica

Published on Apr 1, 2012in Molecular Biology Reports1.402
· DOI :10.1007/S11033-011-1244-X
Cristhian Sanchez-Cruz2
Estimated H-index: 2
(UACM: Universidad Autónoma de la Ciudad de México),
Mavil López-Casamichana6
Estimated H-index: 6
(UACM: Universidad Autónoma de la Ciudad de México)
+ 1 AuthorsJosé de Jesús Olivares-Trejo13
Estimated H-index: 13
(UACM: Universidad Autónoma de la Ciudad de México)
Entamoeba histolytica is a human pathogen, which can survive using haemoglobin (Hb) as only iron supply. Two probable haemophores (Ehhmbp26 and Ehhmbp45) are involved in iron acquisition in this parasite. However, mechanisms related to their transcriptional regulation have not been studied yet. In the present work, transcriptional profiles of both genes were evaluated in trophozoites cultures grown with different iron sources. ehhmbp26 gene was repressed totally by free iron, whereas ehhmbp45 gene showed clearly detectable mRNA levels. Expression profiles for both genes were significantly increased under iron privation condition. Interestingly, ehhmbp26 transcript was highly expressed by Holo-transferrin presence. This induction appears to be independent of direct contact between these proteins, because, in vitro assays evidenced that Ehhmbp26 protein was unable to bind this metalloprotein. Besides, in silico analysis of promoter nucleotide sequences of ehhmbp26 and ehhmbp45 genes revealed some distinctive core promoter elements described in E. histolytica and T-rich regions. Taking altogether these data suggest in E. histolytica dissimilar transcriptional mechanisms involved on iron acquisition control the expression of these genes, and they are unlike to those previously described for instance: in bacteria. Our findings evidenced this pathogen regulates the expression of ehhmbp26 and ehhmbp45 genes depending on the available iron supply, always ensuring the success of its infective process.
📖 Papers frequently viewed together
13 Citations
12 Citations
1 Author (Ghassan Handal)
#1Areli Cruz-Castañeda (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 4
#2Mavil López-Casamichana (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 6
Last. José de Jesús Olivares-Trejo (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 13
view all 3 authors...
Entamoeba histolytica is a human pathogen which can grow using different sources of iron such as free iron, lactoferrin, transferrin, ferritin or haemoglobin. In the present study, we found that E. histolytica was also capable of supporting its growth in the presence of haem as the sole iron supply. In addition, when trophozoites were maintained in cultures supplemented with haemoglobin as the only iron source, the haem was released and thus it was introduced into cells. Interestingly, the Ehhmb...
14 CitationsSource
#2Nidia León-Sicairos (Autonomous University of Sinaloa)H-Index: 20
Last. Mireya de la GarzaH-Index: 21
view all 8 authors...
Abstract Iron is essential for nearly all organisms; in mammals, it is part of proteins such as haemoglobin, and it is captured by transferrin and lactoferrin. Transferrin is present in serum, and lactoferrin is secreted by the mucosa and by neutrophils at infection sites, as a host iron-withholding response, sequestering iron away from invading microorganisms. Additionally, all cells contain ferritin, which sequesters iron when its intracellular levels are increased, detoxifying and preventing ...
24 CitationsSource
#1Areli Cruz-Castañeda (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 4
#2Javier Hernández-Sánchez (IPN: Instituto Politécnico Nacional)H-Index: 9
Last. José de Jesús Olivares-Trejo (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 13
view all 3 authors...
The capability of Entamoeba histolytica to use hemoglobin (Hb) as an iron source has been documented. However, the underlying mechanism to acquire iron from this source is poorly understood. In the present work, an in silico analysis in the E. histolytica genome (Pathema database) allowed us to identify a gene coding for a putative 26-kDa protein (Ehhmbp26) which contains the motifs necessary for Hb-binding. The purified Ehhmbp26 protein was able to bind Hb. Albeit with less efficiency, trophozo...
10 CitationsSource
#1Areli Cruz-Castañeda (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 4
#2José de Jesús Olivares-Trejo (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 13
Hemoglobin-binding proteins are necessary for pathogens to obtain iron from Hb. Entamoeba histolytica can grow using Hb as source of iron, but the underlying mechanism has not previously been established. In this work, we identified a 45 kDa Hb-binding protein of E. histolytica, which we named Ehhmbp45. In silico analysis showed that Ehhmbp45 contains the conserved domains needed for Hb-binding, while overlay assays demonstrated that Ehhmbp45 is able to bind Hb. In addition, we found that Ehhmbp...
12 CitationsSource
#1Lakshminarayan M. Iyer (NIH: National Institutes of Health)H-Index: 21
#2Vivek Anantharaman (NIH: National Institutes of Health)H-Index: 42
Last. L. Aravind (NIH: National Institutes of Health)H-Index: 134
view all 4 authors...
Abstract Comparative genomics of parasitic protists and their free-living relatives are profoundly impacting our understanding of the regulatory systems involved in transcription and chromatin dynamics. While some parts of these systems are highly conserved, other parts are rapidly evolving, thereby providing the molecular basis for the variety in the regulatory adaptations of eukaryotes. The gross number of specific transcription factors and chromatin proteins are positively correlated with pro...
212 CitationsSource
#2Consuelo GómezH-Index: 7
Last. Mario A. RodríguezH-Index: 18
view all 6 authors...
Background The Entamoeba histolytica EhrabB gene encodes for a Rab GTPase involved in phagocytosis. It is located at a virulence locus where the Ehcp112 gene is in the complementary strand at 332 bp of EhrabB start codon, suggesting a finely regulated transcription of both genes. However, the transcription regulation in this parasite is poorly understood.
20 CitationsSource
#1Jason A. Hackney (Stanford University)H-Index: 4
#2Gretchen M. Ehrenkaufer (Stanford University)H-Index: 13
Last. Upinder Singh (Stanford University)H-Index: 31
view all 3 authors...
Few transcriptional regulatory networks have been described in non-model organisms. In Entamoeba histolytica seminal aspects of pathogenesis are transcriptionally controlled, however, little is known about transcriptional regulatory networks that effect gene expression in this parasite. We used expression data from two microarray experiments, cis-regulatory motif elucidation, and a naive Bayesian classifier to identify genome-wide tran- scriptional regulatory patterns in E. histolytica. Our algo...
29 CitationsSource
#1Jean François Marquis (McGill University)H-Index: 1
#2Philippe Gros (McGill University)H-Index: 114
Iron is a co-factor for several essential enzymes and biochemical pathways, including those required for replication of pathogens such as Leishmania in macrophages. Iron acquisition is emerging as a key battleground in which the iron import systems of microbes are pitted against the iron withdrawal and sequestration systems of macrophages, with both competing for iron at the interface of host–pathogen interaction. The recent characterization of a ferrous iron transport system (LIT1) in Leishmani...
31 CitationsSource
#2Magda Reyes-LópezH-Index: 14
Last. Mireya de la GarzaH-Index: 21
view all 7 authors...
Entamoeba histolytica is an enteric protozoan that exclusively infects human beings. This parasite requires iron for its metabolic functions. Lactoferrin is a mammalian glycoprotein that chelates extracellular iron on mucosal surfaces, including the surface of the large intestine, where E. histolytica initiates infection. This work examined the interaction in vitro of E. histolytica trophozoites with human hololactoferrin (iron-saturated lactoferrin). A minimum concentration of 50 μM Fe from hol...
41 CitationsSource
#1E. Flores-Soto (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 2
#2Elisa Azuara-Liceaga (UACM: Universidad Autónoma de la Ciudad de México)H-Index: 8
Last. Esther Orozco (CINVESTAV)H-Index: 29
view all 4 authors...
Abstract Ehcp112 encodes the Entamoeba histolytica EhCP112 cysteine protease that is part of the EhCPADH complex. By in silico analysis we identified putative transcription factor-binding sites along 837 bp upstream the Ehcp112 gene ATG codon. A TATA-like motif (TATATAAA) was located at −36 to −29 bp, a GAAC box (GAACC) was found at −10 to −14 bp and an Inr sequence (TTCAAC) at −8 to −2 bp. These tripartite promoter elements are in non-canonical positions, downstream the transcription initiation...
9 CitationsSource
Cited By2
#1Liliana Soto-Castro (Autonomous University of Sinaloa)H-Index: 2
#2Laura Yuliana Plata-Guzmán (Autonomous University of Sinaloa)H-Index: 2
Last. Claudia León-Sicairos (Autonomous University of Sinaloa)H-Index: 5
view all 10 authors...
In Entamoeba histolytica, iron modulates virulence and gene expression via unknown regulatory mechanisms. The existence of a posttranscriptional iron regulatory system parallel with the iron-responsive element (IRE)/iron regulatory protein (IRP) system in the protozoan Trichomonas vaginalis has recently been reported. Due to their evolutionary closeness and the importance of iron for growth and virulence in these protozoa, we hypothesized the existence of an IRE/IRP-like mechanism in E. histolyt...
5 CitationsSource
#1Elisa E. Figueroa-Angulo (CINVESTAV)H-Index: 9
#2Jaeson S. Calla-Choque (UPCH: Cayetano Heredia University)H-Index: 1
Last. Rossana Arroyo (CINVESTAV)H-Index: 27
view all 4 authors...
Iron homeostasis is highly regulated in vertebrates through a regulatory system mediated by RNA-protein interactions between the iron regulatory proteins (IRPs) that interact with an iron responsive element (IRE) located in certain mRNAs, dubbed the IRE-IRP regulatory system. Trichomonas vaginalis, the causal agent of trichomoniasis, presents high iron dependency to regulate its growth, metabolism, and virulence properties. Although T. vaginalis lacks IRPs or proteins with aconitase activity, po...
7 CitationsSource